1. Field of the Invention
The invention is based on a switching device. A switching device of this type is preferably used in a high-voltage power supply and preferably serves there to switch large currents having a high transient recovery voltage rate.
2. Discussion of Background
The invention refers to a prior art such as is specified, for example, in U.S. Pat. No. 4,087,664. A switching device for a high-voltage power supply described in this prior art contains two current connections, between which a compressed gas-blast circuit-breaker having SF.sub.6 as quenching gas and a vacuum circuit-breaker are arranged in series. The vacuum circuit-breaker is designed such that it can carry and switch both rated and short-circuit currents. Such a vacuum circuit-breaker is therefore very costly. In addition, the vacuum circuit-breaker is driven separately from and in synchronism with the compressed gas-blast circuit-breaker. Since the vacuum circuit-breaker has a considerably smaller travel than the compressed gas-blast circuit-breaker, this produces, moreover, a considerable outlay for the drive and control of the vacuum circuit-breaker. In addition, the vacuum circuit-breaker requires a very high contact pressure force in order to prevent premature lifting off of its electrodes, through which, if appropriate, short-circuit current flows, in the switched-on state.